Essay, PART 2: Getting the tail up... - Page 3 - ED Forums
 


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Old 12-20-2016, 08:22 AM   #21
Sporg
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Quote:
Originally Posted by Friedrich-4/B View Post
Thanks once again Chief, for a great, easy to understand essay. A couple of questions:

Watching this clip, the pilot started lifting the tail very early in the take-off (from c. 2:25 on) - is this about right, or would a more heavily loaded wartime Spitfire need more time before lifting the tail?



How much of an effect does the airfield surface have on the take-off?
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Originally Posted by Chief Instructor View Post
Hi Friedrich-4/B,

Your video link isn't working for me but... There is no right or wrong time to lift the tail. My advice is to lift it as soon as you have enough stabiliser authority to do so. If you can raise the tail, then that's a good time! There's a trick you can do in some high performance aerobatic tail draggers such as an Extra or Edge where you can hold the aircraft stationary on the brakes and lift the tail with the prop slipstream alone. Not very useful but a good demonstration of how the propwash affects the authority of the tail surfaces!

Ground surface has a big effect on controlability. Smooth grass tends to be the easiest because the main wheels can slip a little, allowing greater forgiveness when it comes to lateral interactions between the gear and the ground. Dry tarmac is the trickiest because higher grip levels translate every sideways force back to the airframe. Having said that, the high grip surfaces allow for much more accurate control, provided you know what you're doing. Training new pilots is often best done on the grass to build confidence, then progressing to hard surfaces once they have the right picture and feel. Does that answer your questions?

Best wishes,

CFI
Chief Instructor, thanks for very good explanation.

It's interesting to see another technique in use here:
This guy gives moderate and then increasing throttle, and keeps the tail on the ground until it lifts naturally by the speed:



(Check at 1:27)

This is the technique I have had success with in the DCS Spitfire.

It seems like the guy in the first link deliberately lifted the tail as early as he could (maybe to get it into the slipstream), while this last guy just let it lift itself.

(Btw, Friedrich, I corrected your link: When embedding video, only include the video ID, not the whole link.)
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Old 12-20-2016, 09:54 AM   #22
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I prefer increasing thrust slowly else the wings go rocking. i tried to raise the tail but you know i broke the prop
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Old 12-20-2016, 09:58 AM   #23
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Another great essay Chief, I've long been lifting the tail during my takeoff run but I'd never had the why's and where's explained so well. Really interesting to hear the theory behind it.

A couple of things to add. Personally I like to trim the nose down a bit more than suggested in the manuals, especially in the 190 where I go full nose down trim. I find trimming the nose down more naturally leads to the tail lifting before the plane tries to takeoff. Maybe something for people to experiment with and see what works for them.

Also personally I have a FFB stick and so I rest it fully back before takeoff and then let the stick centre itself as the airspeed increases. It happens naturally around the right speed and tends to give a nice smooth transition, I find. I've also found centering the stick too early is better than too late, especially in the 190.

Also just a note that I've found once you've got the tail up you really have to keep on top of the rudder. More in some planes than in others (I'm looking at you 190). You can anticipate the yaw left due to the transition and you have to dance on the rudders to keep it straight. The good news is that the rudder dancing is easier with the nose up as you can see the horizon out the front.

Last edited by Tomsk; 12-20-2016 at 10:01 AM.
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Old 12-20-2016, 10:23 AM   #24
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Still to get to grips with the Spit

But I notice the precession of the prop disc on both the Dora and Kurfurst.

It took me a good number of attempts to get these off the runway in a (somewhat) tidy manner and a large part of that was the sudden kick as the tail came up.

It's especially pronounced on the 109 with the smaller rudder and needs a hefty right boot followed in quick succession by a lighter left boot, well that's how I overcome it.

If I had read this prior to trying takeoffs I could have saved Germany a shed load of broken aircraft

You's have thought I'd have known this from many hours on a motorcycle!!!!

Anyway Thanks for the lectures I'm going to copy and save them somewhere for future reference

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Old 12-20-2016, 10:43 AM   #25
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I think i can try the take off in the 185F in Xplane and then see how good i am in DCS. It's the tail thing

Both the essays from chief are worth printing out now i gotta find a printer
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Old 12-20-2016, 11:16 AM   #26
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BTW P-factor would also occur with the tail draggers during take off roll ?
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Old 12-20-2016, 11:46 AM   #27
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Thanks for taking the time to post these essays Chief. Great reading and very much appreciated.
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Old 12-20-2016, 07:04 PM   #28
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made 3 successful takes off but without the tail up , and almost stalled but i just can't seem to make the tail go up as the nose drills a hole into the ground more practice
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Old 12-20-2016, 07:05 PM   #29
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Quote:
Originally Posted by humptydumpty View Post
BTW P-factor would also occur with the tail draggers during take off roll ?
Yep, particularly on taildraggers, due to the even more pronounced difference in AoA of the downgoing prop blades...
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Old 12-20-2016, 07:42 PM   #30
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Simply(!), thank you.
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